In the last decade, the use of deep brain stimulation (DBS) has demonstrated dramatic improvement in symptoms associated with movement disorders, including symptoms from Parkinson's disease (PD), Essential Tremor (ET) and dystonia.
Essential Tremor is an involuntary movement, such as a shaking movement that is repeated over and over. Essential Tremor usually affects the hands and head, although occasionally the feet or torso may also be affected. Essential tremor, which sometimes runs in families, is one of the most common types of tremor. It causes shaking that is most noticeable when a person is performing a task like lifting a cup or pointing at an object. The shaking does not occur when the person is not moving. The tremor may also affect the person's voice. Medication can help reduce the shaking. Tremors can also be caused by conditions or medications that affect the nervous system, including Parkinson's disease, liver failure, alcoholism, mercury or arsenic poisoning, lithium, and certain antidepressants.
Instead of destroying the overactive cells that cause symptoms from PD, for example, DBS instead temporarily disables the cells by firing rapid pulses of electricity between four electrodes at the tip of a lead. The lead is permanently implanted and connected to a pacemaker controller installed beneath the skin of the chest.
DBS utilizes electrodes that are usually implanted in one of three regions of the brain: the thalamic nucleus ventral is intermedius (Vim), the internal globus pallidus (GPi), and the subthalamic nucleus (STN) (FIG. 1). Some studies have shown that DBS has the best effect on tremors, when the Vim is stimulated. Rigidity and gait disturbances have shown improvements with stimulation of GPi and STN. The parameters of 130-185 Hz, 60 ms pulse width and 2.5 to 3.5 volts are most commonly utilized for DBS stimulation. DBS stimulation is typically pulsed intermittent stimulation having an on cycle of about a few seconds up to a minute, then an off cycle for about 30 seconds to several minutes.
The challenge of DBS is the obvious drawback of having to undergo a neuro-surgical procedure and also to have the result of one or two electrodes implanted deep within the structures of the brain.
The present invention achieves tremor control through brain stimulation without the use of the invasive DBS electrodes. Stimulation of peripheral nerves results in the excitation of some area of the brain (Thalmus, sub-cortical and Cortical areas). The stimulation of sites on the surface of the skin produces effects of tremor control which are similar to the effects achieved by DBS for limited amounts of time. Surface stimulation is achieved through the use of surface electrodes that are currently used for Muscle Stimulation or TENS. Following a 30-60 minute stimulation time, there is a residual decrease in tremor of at least 30-60 minutes. The device can be worn under the clothing and activated while the decreased tremor period is desired.
PET (Positron Emission Tomography) scans, a molecular medical imaging procedure that uses small amounts of radioactive pharmaceuticals to make images of the body's metabolic activity, Magnetoencephalography (MEG) scans and fMRI scans can be used to identify appropriate peripheral surface stimulation sites. Various types of stimulation can be used including TENS, Neuro-Muscular Stimulation, Ultra Sound, Interferential Stimulation, PEMF, EMF, and various types of mechanical stimulation.
Thus, a heretofore unaddressed need exists in the industry to address the aforementioned deficiencies and inadequacies associated with a neuro-surgical procedure and the implantation of at least one electrode deep within the structures of the brain.